Conventionally, a semiconductor device using a silicon carbide (SiC) has been known (for example, WO01/018872 (hereinafter, referred to as Patent Document 1)). Patent Document 1 describes that a SiC substrate of 4H (Hexagonal) poly type having a plane orientation of almost {03-38} is used to form a Metal-Oxide-Semiconductor Field-effect Transistor (MOSFET). It is also described that in the MOSFET, a gate oxide film is formed by means of dry oxidation (thermal oxidation). Patent Document 1 describes that such a MOSFET achieves large channel mobility (approximately 100 cm2/Vs).